Air pollution appears to have decreased in urban areas across the world as cities continue to be locked down to prevent the spread of coronavirus.

In Europe, cities including Brussels, Paris, Madrid, Milan and Frankfurt showed a reduction in average levels of noxious nitrogen dioxide from 5 to 25 March, compared with the same period last year, according to new satellite images.

The images, released by the European Space Agency, show the changing density of nitrogen dioxide, a harmful gas emitted when fossil fuels are burnt at high temperatures, most commonly at power plants and in motor vehicles.